1. Technical Field
The present invention relates to an optical device and a projector.
2. Related Art
A previously well-known projector is provided with a light modulation device, a projection optical device, and a retention member. The light modulation device modulates lights of three colors of RGB (Red, Green, and Blue) in accordance with image information on a color light basis. The projection optical device magnifies and projects image lights as a result of modulation by the light modulation device, and the retention member keeps hold of the light modulation device and the projection optical device. An example includes Patent Document 1 (JP-A-2000-258840).
With such a projector of Patent Document 1, a prism unit, i.e., light modulation device, is disposed on the bottom surface of a head body, i.e., retention member, shaped substantially like a letter L when viewed from the side, and the bottom surface of the head body is fixed to a lower case. The head body is fixed with, on its side surface, a projection lens, i.e., projection optical device, so that the space between the prism unit and the projection lens is kept substantially constant, and their optical axes are substantially matched.
The concern here is the heavy weight of the projection lens, and with the projector of Patent Document 1, when the head body keeping hold of the prism unit and the projection lens is under a large force due to the self weight of the projection lens or an impact applied to the projector, for example, there is a risk that the head body would be deformed. If the head body is deformed as such, because the prism unit is disposed on the bottom surface of the head body fixed to the lower case, the space between the prism unit and the projection lens may show a change, or some skewness may be observed between their optical axes. As a result, the projector may be problematically deteriorated in terms of optical capabilities. Especially when the projector is of a short-range type with a wide-angle projection lens, the optical capabilities are easily influenced by the skewness of the optical axes between the light modulation device and the projection lens. Therefore, such a problem of deterioration of the optical capabilities becomes obvious.